Hammer



FIG. 1 is a front elevational view of a hammer showing my new design, the back view being a mirror image of this front view;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a right side elevational view thereof; and

FIG. 5 is a left side elevational view thereof. 

The ornamental design for a hammer, as shown and described. 